Transcript Wide Area Network - Clydebank High School

Networking
Two or more computers linked together so that it is capable
of sending messages between them.
Network
Stand Alone Computer
Local Area Network (LAN)
Cover a small area such as a room or a building.
Schools
Office Buildings
Advantages
• Share data and programs between stations.
• Share peripherals, such as, printers, scanners. (Resource
Sharing)
• Email other stations.
• Kept secure by use of passwords - Unauthorised interference
can be reduced.
• Log on to any station on the network
Wide Area Network (WAN)
A computer network that spans a relatively large geographical
area. The Internet is the best-known example of a wide area
network.
On-Line
Connected to a network. Logging on to a file server.
Off-Line
Logging off of a network. Not connected to a network.
Cables and Wireless
Cables
There are two common types of cables used:
1. Unshielded Twisted pairs of copper wire(UTP)
2. Optical Fibre Cable
Optical Fibre Cable
Unshielded Twisted pairs (UTP)
Copper wire carries electrical
signals
Very fine strands of glass
that can transmit data very
rapidly by using beams of
light
Unshielded Twisted pairs (UTP)
Advantage
Disadvantage
• Cheap
• Interference can occur
• Can be tapped into
Optical Fibre Cables
Advantage
Disadvantage
• Data is transmitted faster
• Expensive
• Does not corrode
Wireless
A method or way of transmitting data without using a physical
connection. E.g radio wave or infrared.
• Infrared Communication
• Bluetooth
• WiFi
• Microwave Transmisson
• Satellite Links
Infrared Communication
Uses the same system as your TV remote. Used for short
range communication. Sunlight can interface.
Bluetooth
This replaces infrared uses radio waves. Used for short
range transmission. Mobile phones or PDA use bluetooth.
WiFi (Wireless Fidelity Alliance)
Connect to the network using radio signals, and computers
can be up to 100 feet or so apart.
These are examples of LAN
Wide Area Networks
Wide area networks use telecommunications links to transmit
and receive data.
Telecommunication links used in wide area networks include:
• Microwave Transmission
• Satellite Links
• Optical Fibre
Microwave Transmission
Many public telephone services use this. Use dish aerials
Satellite Links
Operates over long distance. Used for public telephone
service for links with overseas.
Network Security
Network Manager - decides on each users access level for
a network. He decides on usernames and passwords.
Passwords
A secret code that you would use to gain access to a
computer. Must be changes regularly and should not be to
easy.
Encryption
Putting data into a code or scrambling it to prevent it being
seen.
Physical Methods
Locking the computer room or the disks away.
Using magnetic strip cards to enter a room.
Finger print scanning (this is known as bioscrypt)
Setting up WiFi – Credit
• Wireless Network Interface Card
• Create a Hotspot
(Wireless Access Point Router)
A hotspot is a connection point for a WiFi network. It is a
small box that is hardwired into the internet.
There are many WiFi hotspots now available in public places
like restaurants, hotels, airports.
Client and Server
Client
A client is usually a desktop computer. A client accesses the
server for files, data and programs.
Server
A server device hosts files, databases, Web sites, or other
applications. Server devices often feature higher-powered
processors, more memory, and larger disk drives than
clients.
Server
Clients
Types
File server (School)
Printer Server
Web Server
Database Server (multi access)
Multi Access (2 Marks)
Many users at the same time
Network Interface Card
Allows a computer to connect to a network.
Wireless Network Interface Card
Allows a computer to connect to a wireless network. Most
laptops come fitted with this card.
Multi Access
Many users may be on-line to a computer system at the same
time.
Multi Access Systems:
Airline Reservation
Police National Computer
Automated telling (cash machines) machines
A client and server is also an example of a multi-access system.
Teleworking
Work from home using a WAN. (connected to the internet)
Advantages
• Do not have to travel to work which reduces pollution and
congestion (traffic)
• Look after young family (save money on child care)
• Employers save money on office space
• Take breaks when you want
Laws
•Data Protection Act
Protects data on a computer
•Copyright, Design and Patents Act
Protects music, books and logos, movies
•Computer Misuse Act
Hacking and Viruses